1. Technical Field
The present invention relates to a common mode filter, and more particularly, to a common mode filter having a coil electrode formed on both surfaces of a core layer and a method of manufacturing the same.
2. Description of the Related Art
In accordance with a development of technology, electronic devices such as a portable phone, home appliances, a personal computer (PC), a personal digital assistant (PDA), a liquid crystal display (LCD) and the like have converted from the analog method to the digital method and have high-speed characteristics due to an increase in an amount of data to be processed. Therefore, USB 2.0, USB 3.0, and a high-definition multimedia interface (HDMI) have come into wide use as a high-speed signal transmission interface and have been used in many digital devices such as a personal computer and a digital high-definition television.
These interfaces employ a differential signal system transmitting a differential signal (a differential mode signal) using a pair of signal lines unlike a single-end transmission system generally used for a long time.
Therefore, in order to remove common mode noise, a common mode filter is generally used in a high-speed differential signal line and the like. Here, the common mode noise is noise generated in the differential signal line, and the common mode filter removes the noise capable of being removed by an existing electromagnetic interference (EMI) filter.
Referring to Japanese Patent Laid-Open Publication No. 2012-015494, a general common mode filter according to the related art has a structure in which a pair of primary and secondary conductor coils are included in an insulating layer and the primary and secondary conductor coils are spaced from each other having an insulating resin configuring the insulating layer therebetween. In order to manufacture the common mode filter having the above-mentioned structure, processes of applying the insulating resin and plating the coil electrode are needed to be repeatedly performed by generally performing a build-up process.
However, this causes an increase in process number according to a laminating number of the conductor coils to thereby become a factor of decreasing productivity and increasing manufacturing costs. Therefore, a technology capable of manufacturing the common mode filter using a simpler method is urgently demanded.